Reagents and solvents were used as received
from commercial suppliers unless noted otherwise. All reactions were
performed in oven-dried or flame-dried glassware and were monitored
by thin-layer chromatography. Flash column chromatography was performed
using silica gel (300–400 mesh). 1H NMR and 13C NMR (75 MHz) spectra were recorded at 300 or 500 MHz by
a NMR spectrometer in DMSO-d6 or CDCl3. Chemical shifts (δ) were given in ppm relative to
CDCl3 (7.26 ppm for 1H and 77 ppm for 13C) or internal tetramethyl silane (δ = 0 ppm) as internal standard.
Data were reported as follows: chemical shift, multiplicity, coupling
constants, and integration. HRMS spectra were obtained using APCI-TOF
in the positive mode. UV–vis absorption spectra were recorded
on a Shimadzu UV-4100 spectrophotometer, and fluorescence spectra
were recorded on a Hitachi F-4500 fluorescence spectrophotometer,
with a quartz cuvette (path length = 1 cm).
from commercial suppliers unless noted otherwise. All reactions were
performed in oven-dried or flame-dried glassware and were monitored
by thin-layer chromatography. Flash column chromatography was performed
using silica gel (300–400 mesh). 1H NMR and 13C NMR (75 MHz) spectra were recorded at 300 or 500 MHz by
a NMR spectrometer in DMSO-d6 or CDCl3. Chemical shifts (δ) were given in ppm relative to
CDCl3 (7.26 ppm for 1H and 77 ppm for 13C) or internal tetramethyl silane (δ = 0 ppm) as internal standard.
Data were reported as follows: chemical shift, multiplicity, coupling
constants, and integration. HRMS spectra were obtained using APCI-TOF
in the positive mode. UV–vis absorption spectra were recorded
on a Shimadzu UV-4100 spectrophotometer, and fluorescence spectra
were recorded on a Hitachi F-4500 fluorescence spectrophotometer,
with a quartz cuvette (path length = 1 cm).